[roll] Roll fuchsia [kernel][vm][arm64] Disallow executable + uncached mappings

This doesn't seem sensible and the related executable-gated code assumes
cached (which was tickled in a recent bug where MMIO was wrongly marked
as executable).

Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1279924
Original-Revision: 0b99b55ff8cf75c1d957284e5429ecb54fc218ec
GitOrigin-RevId: 161d3655994da96d2b3fd905e38fd07648ccf183
Change-Id: I525aaf5376ee88691e604d04ea91baff83f61f4b

Author: Joshua Seaton

stem

@@ -8,7 +8,7 @@
              root=""
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="7843cc7376e340e0272918437f10d071459f9495"
+             revision="0b99b55ff8cf75c1d957284e5429ecb54fc218ec"
              />
   </imports>
   <projects>